Telephone system



June 28, 1932. F. WOLF TELEPHONE SYSTEM Filed Nov. 17. 1950 h NYMHH m: hum z 9 14%.

Patented June 28, 1932 UNITED STATES PATENT OFFICE FRITZ WOLF, OF BERLIN, GERMANY, ASSIGNOR T0 SIEMENS & HALSKEAKTIENGESETIL- SCHAFT, OF SIEMENSSTADT, NEAR BERLIN, GERMANY TELEPHONE SYSTEM Application filed November 17, 1930, Serial No. 496,059, and in Germany December 12, 1929.

The invention relatesto a telephone system in which toll lines are multipled in a number of operators positions but are provided with answering jacks at only one position, the answering jacks being distributed among the difierent positions according to the usual practice.

The object of the invention is to reduce the number of devicesused by an operator at her position to indicate Whether a toll line is engaged or disengaged. This is effected in a particularly simple manner by providing the connecting arrangements (cord circuits) at each operators position with switching devices which can only effect the through connection of a line after a manual operation has been performed at the operators position to which the required toll line is allotted as a calling line.

An example of the operation of the invention is shown in the accompanying illustration in which two operators positions PLl and PL2 are shown together with the necessary answering jacks AKl, AK2 and calling or multiple jacks VKl, VK2, belonging, respectively, to the long distance lines F1 and F2. The cord circuit is shown for the operators position PLl only.

The arrangement operates in the following manner:

When a call is received at the operators position PLl over the line F1 relay. A1 responds over its I winding, closes the contact lal and thereby causes the lamp ALl to be lighted over the circuit: earth, battery, lamp ALl, contacts lal, earth. Relay A1 remains attracted over its II winding in the circuit: earth, contacts lal, 2t1, Winding II of relay A1, battery, earth. The operator outs the plug Stl into the jack AKl where y relay C1 is operated over the circuit: earth, Windings II and I of relay C1, plug Stl, jack AKl, c-leaol of the line F1, to battery and earth in the allotted connecting device not shown in the diagram. Relay C1 then short circuits its high resistance winding II through its contact 301 and thereby prevents the engaged line from being seized in known manner. Simultaneously with'the operation of relay C1 the relay T1 is energized over the circuit: earth, battery, relay T1, c-lead, line F1, jack AKl', plug Stl, relay ()1, earth. Relay T1 responds and opens its contacts 1761 and 1861 so that the relay A1 cannot be energized again during the connection by Y a call over another line in whatever way it may be connected to the line F1. Relay C1 also closes its contacts 101 and 501. The operator now operates the key T and opens contacts 6 and 7 and closes contacts 8 and 9 respectively, and thereby connectsher set Abf to the calling line F 1. She inquires as to the number and location of the wanted party and then communicates over an order Wire (not shown on the drawing) with-the operator at the position PL2, to which toll lines such as F2 extending to the desired point are allocated as calling lines. The second operator now notes the busy or idle condition of the lines in the desired group and tells the first operator which one to use. Assuming that toll line F2 is the one selected, the second operator operates the key T62 whereby acircuit for relay C2 in the first operators cord circuit is prepared by connecting the sleeve of jack VK2 to the winding of relay T2.

The operator at position PLl now inserts the plug S252 in the jack VK2 and closes the circuit prepared for relay G2 with the result that this responds over the circuit; earth windings II and I of relay C2, plug St2, jack VK2, c-lead of the line F2, contact 10 or the switch operated by the key T52, relay T2, battery, earth. Relay C2 closes its contact 1102 and guards the engaged linefrom being seized by the short circuiting of its winding II. In addition it closes its contacts 1202 and 1302 to which the calling line F 1 is connected to the required line F2 by the return of the answering key to close contacts 6 and 7. The insertionof the plug St2 in the jack VK2 also operates relay T2 in series with relay C2 causing its contacts 1M2 and 15t2 to open so that relay A2 cannot be energized by an incoming call transmitted by one line or another connected to the line F2. i I

When the conversation is finished and the operator at the positionPLl has; received a disconnect signal in known manner, she pulls out the plugs Stl and $22. The circuit for relays C1 and T1 is thus broken, these relays thereby releasing. When this takes place the contacts 301, lcl and 501 are opened and 2t1, 17t1, 18t1 and 21t1 are closed. The circuit for rela s C2 and T2 is also broken with the result t at the contacts 1102, 1202 and 1302 are opened and 1&2, 15t2, 16t2 and 1922 are closed. The key T62 still being depressed, the operator at the position PL2 is notified by the lighting of the lamp SL2 over the circuit: earth, battery, contact l6 t2 lamp SL2, contact 20, closed by the switch effected by key T122, earth, that the conversation is finished. She puts the key Tb2 into its normal position so that everything is restored to its original condition.

What is claimed is:

1. In a telephone system, two switchboards, a group of trunks terminating in answering jacks in the first switchboard and in multiple jacks in the second switchboard, a second group of trunks terminating in answering jacks" in the second switchboard and in multiple jacks in the first switchboard, a cord circuit at the first switchboard for connecting trunks of the first and second groups by Way of their respective answering and multiple jacks, and means controlled from the second switchboard for completing the connection by closing normally open points in the cord circuit.

2. In a telephone system, two switchboards, a group of trunks terminating in answering 'acks in the first switchboard and in multiple acks in the second switchboard, a second group of trunks terminating in multiple jacks 1n the first switchboard and in answering jacks in the second switchboard, a cord circuit at the first switchboard for establishing connections between a trunk line in the first group and a trunk line in the second group, a plurality of normally open points in the talking strands of said cord circuit, means for automatically closing certain of the normally open points in the cord circuit when the operator at the first switchboard plugs 't into, an answering jack, and means con- I trolled by the operator at the second switchboard for closing the remaining normally open points in the cord circuit when the operator at the first switchboard plugs it into a multiple jack;

3. In a telephone system, two switchboards, a group of trunks terminating in answering jacks in the first switchboard and in multiple jacks in the second switchboard", a second group oftrunks terminating-in multiple jacks in the first switchboard and in answering jacks; in the second switchboard, a cord circuitat the first switchboard for: establishing connections between a trunk line in the first group and a trunk line in the second group, a pl'u'ral-ityof normally open points in the talking strands of said cord circuit, means for automatically closing certain of the normally open points in the cord circuit when the operator at the first switchboard plugs it into an answering jack, means controlled by the operator at the second switchboard for closing the remaining normally open points in the cord circuit when the operator at the first switchboard plugs it into a multiple jack, and means for automatically signalling said second operator when said first operator removes the cord from the multiple jack.

4-, In a telephone system, a cord circuit having a plurality of normally open points in the talking strands, answering and multiple jacks, a relay for closing certain of the normally open points when one end of the cord circuit is plugged into an answering jack, another relay for closing the remaining normally open points when the other end of the cord circuit is plugged into an assigned mul tiple ack, and means for controlling the operation of said second relay at the position assigning the multiple jack.

5. In a telephone system, an operators position, incoming and outgoing trunk lines, a cord circuit at said position for connecting the trunk lines, said cord circuit having normally open points in the talking strands, a relay for closing said normally open points, another operators position for assigning outgoing trunks, and means at said assigning operators position for controlling the operation of said relay.

6. In a telephone system, a trunk line terminating in an answering jack and a plurality of multiple jacks, a relay permanently connected to the sleeve of said answering ack, means for operating said relay when a call over said trunk line is answered, means for connecting said relay to the sleeve of each of said multiple jacks when a call is to be extended over said trunk line, a signal operative responsive to the last mentioned means, and means responsive to the extension of said call over said trunk line for operating said relay to disconnect said signal.

7. In a telephone system, a trunk line terminating in an answering ack at one position and in a multiple jack at another position, a relay at said answering position per- 1 manently connected to the sleeve of said answering jack, means for operating said relaywhen a call over said trunk line is answered, means at said answering position for connecting said relay to the sleeve of said multiple jack when a call is to be extended over said trunk line, a signal at said answering position operative responsive to the last mentioned means, and means responsive to the extension of'said call over said trunk line for operating said relay to disconnect said signal.

8'. Ina telephone system, a trunk line terminatingin 'an answeringjfack and a plurality of multiple jacks, said answering jack being located at a first operators position,

and each one of said multiple jacks being located at a different operators position, a

cord circuit at said first operators position having normally open points in the talking strands, a current sourcepermanently connected to the sleeve of said answering jack, means responsive to said source for closing the normall open points in said cord circuit when said lii'st operator answers a call over said trunk line, and manually controlled means at said first operators position for connecting said source to the sleeve of said multiple jacks when any other operator desires to extend a call over said trunk line.

9. In a telephone system, an operators position, a cord circuit thereat having normally open points in the talking strands, an answering jack, means responsive to the plugging in of one end of said cord into said answering jack for dosing certain of said normally open points in said talking strands, multiple jacks, and means responsive to the plugging in of the other end of said cord into an assigned multiple jack for closing the remaining open points in said talking strands.

10. In a telephone system, an operators position, a cord circuit thereat having normally open points in the talking strands, an answering jack, means res onsive to the plugging in of one end of sai cord into said answering jack for closing certain of said normally open points in said talking strands, multiple jacks, means responsive to the plugging in of the other end of said cord into an assigned multiple jack for closing the remaining open points in said talking strands, and means at a second operators position for preventing the remaining open points in the talking strands of said cord circuit from closing when the operator at said first-mentioned operators position plugs said cord into a busy or unassigned multiple jack.

11. In an operators position, a cord circuit having a plurality of normally open points in the talking strands, means responsive to the plugging of said cord into an answering jack for closing certain of the said open points, a second operators position,

multiple jacks at said first position assigned by the operator at said second position, and

means controlled by the operator at said second position for closing of the remainin open points in the talking strands of the cor' circuit when the same is plugged into an assigned multiple jack.

In witness whereof, I hereunto subscribe my name this 24th day of October, A. D.

FRITZ WOLF. 

